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<div class="titlepage"><div><div><h4 class="title">
<a name="boost_asio.reference.cancellation_slot.emplace"></a><a class="link" href="emplace.html" title="cancellation_slot::emplace">cancellation_slot::emplace</a>
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<p>
          <a class="indexterm" name="boost_asio.indexterm.cancellation_slot.emplace"></a> 
Installs
          a handler into the slot, constructing the new object directly.
        </p>
<pre class="programlisting">template&lt;
    typename <a class="link" href="../CancellationHandler.html" title="Cancellation handler requirements">CancellationHandler</a>,
    typename... Args&gt;
CancellationHandler &amp; emplace(
    Args &amp;&amp;... args);
</pre>
<p>
          Destroys any existing handler in the slot, then installs the new handler,
          constructing it with the supplied <code class="computeroutput">args</code>.
        </p>
<p>
          The handler is a function object to be called when the signal is emitted.
          The signature of the handler must be
        </p>
<pre class="programlisting">void handler(boost::asio::cancellation_type_t);
</pre>
<h6>
<a name="boost_asio.reference.cancellation_slot.emplace.h0"></a>
          <span class="phrase"><a name="boost_asio.reference.cancellation_slot.emplace.parameters"></a></span><a class="link" href="emplace.html#boost_asio.reference.cancellation_slot.emplace.parameters">Parameters</a>
        </h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl class="variablelist">
<dt><span class="term">args</span></dt>
<dd><p>
                Arguments to be passed to the <code class="computeroutput">CancellationHandler</code> object's
                constructor.
              </p></dd>
</dl>
</div>
<h6>
<a name="boost_asio.reference.cancellation_slot.emplace.h1"></a>
          <span class="phrase"><a name="boost_asio.reference.cancellation_slot.emplace.return_value"></a></span><a class="link" href="emplace.html#boost_asio.reference.cancellation_slot.emplace.return_value">Return
          Value</a>
        </h6>
<p>
          A reference to the newly installed handler.
        </p>
<h6>
<a name="boost_asio.reference.cancellation_slot.emplace.h2"></a>
          <span class="phrase"><a name="boost_asio.reference.cancellation_slot.emplace.remarks"></a></span><a class="link" href="emplace.html#boost_asio.reference.cancellation_slot.emplace.remarks">Remarks</a>
        </h6>
<p>
          Handlers installed into the slot via <code class="computeroutput">emplace</code> are not required
          to be copy constructible or move constructible.
        </p>
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<td align="right"><div class="copyright-footer">Copyright © 2003-2021 Christopher
      M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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